Optimal time following fluorescein instillation to evaluate rigid gas permeable contact lens fit

PURPOSE: To examine the optimum time at which fluorescein patterns of gas permeable lenses (GPs) should be evaluated. METHODS: Aligned, 0.2mm steep and 0.2mm flat GPs were fitted to 17 patients (aged 20.6±1.1 years, 10 male). Fluorescein was applied to their upper temporal bulbar conjunctiva with a moistened fluorescein strip. Digital slit lamp images (CSO, Italy) at 10× magnification of the fluorescein pattern viewed with blue light through a yellow filter were captured every 15s. Fluorescein intensity in central, mid peripheral and edge regions of the superior, inferior, temporal and nasal quadrants of the lens were graded subjectively using a +2 to -2 scale and using ImageJ software on the simultaneously captured images. RESULTS: Subjectively graded and objectively image analysed fluorescein intensity changed with time (p<0.001), lens region (centre, mid-periphery and edge: p<0.05) and there was interaction between lens region with lens fit (p<0.001). For edge band width, there was a significant effect of time (F=118.503, p<0.001) and lens fit (F=5.1249, p=0.012). The expected alignment, flat and steep fitting patterns could be seen from approximately after 30 to 180s subjectively and 15 to 105s in captured images. CONCLUSION: Although the stability of fluorescein intensity can start to decline in as little as 45s post fluorescein instillation, the diagnostic pattern of alignment, steep or flat fit is seen in each meridian by subjective observation from about 30s to 3min indicating this is the most appropriate time window to evaluate GP lenses in clinical practice.

The influence of end of day silicone hydrogel daily disposable contact lens fit on ocular comfort, physiology and lens wettability

Purpose: To quantify the end-of-day silicone-hydrogel daily disposable contact lens fit and its influence of on ocular comfort, physiology and lens wettability. Methods: Thirty-nine subjects (22.1. ±. 3.5 years) were randomised to wear each of 3 silicone-hydrogel daily-disposable contact lenses (narafilcon A, delefilcon A and filcon II 3), bilaterally, for one week. Lens fit was assessed objectively using a digital video slit-lamp at 8, 12 and 16. h after lens insertion. Hyperaemia, non-invasive tear break-up time, tear meniscus height and comfort were also evaluated at these timepoints, while corneal and conjunctival staining were assessed on lens removal. Results: Lens fit assessments were not different between brands (P > 0.05), with the exception of the movement at blink where narafilcon A was more mobile. Overall, lag reduced but push-up speed increased from 8 to 12. h (P <. 0.05), but remained stable from 12 to 16. h (P > 0.05). Movement-on-blink was unaffected by wear-time (F = 0.403, P = 0.670). A more mobile lens fit with one brand did not indicate that person would have a more mobile fit with another brand (r = -0.06 to 0.63). Lens fit was not correlated with comfort, ocular physiology or lens wettability (P > 0.01). Conclusions: Among the lenses tested, objective lens fit changed between 8. h and 12. h of lens wear. The weak correlation in individual lens fit between brands indicates that fit is dependent on more than ocular shape. Consequently, substitution of a different lens brand with similar parameters will not necessarily provide comparable lens fit.

Objective analysis of contact lens fit

Purpose: To assess the validity and repeatability of objective compared to subjective contact lens fit analysis. Methods: Thirty-five subjects (aged 22.0. ±. 3.0 years) wore two different soft contact lens designs. Four lens fit variables: centration, horizontal lag, post-blink movement in up-gaze and push-up recovery speed were assessed subjectively (four observers) and objectively from slit-lamp biomicroscopy captured images and video. The analysis was repeated a week later. Results: The average of the four experienced observers was compared to objective measures, but centration, movement on blink, lag and push-up recovery speed all varied significantly between them (p <. 0.001). Horizontal lens centration was on average close to central as assessed both objectively and subjectively (p > 0.05). The 95% confidence interval of subjective repeatability was better than objective assessment (±0.128. mm versus ±0.168. mm, p = 0.417), but utilised only 78% of the objective range. Vertical centration assessed objectively showed a slight inferior decentration (0.371. ±. 0.381. mm) with good inter- and intrasession repeatability (p > 0.05). Movement-on-blink was lower estimated subjectively than measured objectively (0.269. ±. 0.179. mm versus 0.352. ±. 0.355. mm; p = 0.035), but had better repeatability (±0.124. mm versus ±0.314. mm 95% confidence interval) unless correcting for the smaller range (47%). Horizontal lag was lower estimated subjectively (0.562. ±. 0.259. mm) than measured objectively (0.708. ±. 0.374. mm, p <. 0.001), had poorer repeatability (±0.132. mm versus ±0.089. mm 95% confidence interval) and had a smaller range (63%). Subjective categorisation of push-up speed of recovery showed reasonable differentiation relative to objective measurement (p <. 0.001). Conclusions: The objective image analysis allows an accurate, reliable and repeatable assessment of soft contact lens fit characteristics, being a useful tool for research and optimisation of lens fit in clinical practice.

Diabetes and contact lens wear

The literature suggests that diabetic patients may have altered tear chemistry and tear secretion as well as structural and functional changes to the corneal epithelium, endothelium and nerves. These factors, together with a reported increased incidence of corneal infection, suggest that diabetic patients may be particularly susceptible to developing ocular complications during contact lens wear. Reports of contact lens-induced complications in diabetic patients do exist, although a number of these reports concern patients with advanced diabetic eye disease using lenses on an extended wear basis. Over the past decade or so, there have been published studies documenting the response of the diabetic eye to more modern contact lens modalities. The results of these studies suggest that contact lenses can be a viable mode of refractive correction for diabetic patients. Furthermore, new research suggests that the measurement of tear glucose concentration could, in future, be used to monitor metabolic control non-invasively in diabetic patients. This could be carried out using contact lenses manufactured from hydrogel polymers embedded with glucose-sensing agents or nanoscale digital electronic technology. The purpose of this paper is to review the literature on the anterior ocular manifestations of diabetes, particularly that pertaining to contact lens wear. © 2012 The Authors. Clinical and Experimental Optometry © 2012 Optometrists Association Australia.

Function of lipids - their fate in contact lens wear:an interpretive review

Lipids play a vital role in the body at many interfaces. Examples include the lubrication of articulating joints by synovial fluid, the coating of the lung by pulmonary surfactant and the functions of the tear film in the protection of the anterior eye. The role of the lipids is similar at each site - acting as boundary lubricants and reducing surface and interfacial tension. This review focuses on how and why contact lens wear can disrupt the normal function of lipids within the tear film and explains how the otherwise advantageous presence and function of tear lipids can become disadvantageous, causing problems for the wearer. Because the contact lens is some ten times thicker than the tear film, lipids deposited on the anterior surface become immobilised, reducing lipid turnover and thus leading to prolonged exposure to oxygen and light with consequent generation of degradation products. These degraded lipids reduce lens wettability and have additionally been linked to problems of contact lens discomfort and intolerance. Lipid problems are influenced by the thickness of the lens, the material, surface modification, mode of wear and ultimately the subject. The most influential of these variables is frequently the subject. © 2012.

CLAE to move to online format

Editorial: The 2015 BCLA annual conference was another fantastic affair. It was the first time the conference was held in the beautiful city of Liverpool. The venue was great and the programme was excellent. The venue overlooked the River Mersey and many of the hotels were local boutique hotels. I stayed in one which was formerly the offices of White Star Liners—where the RMS Titanic was originally registered. The hotel decor was consistent with its historic significance. The BCLA gala dinner was held in the hugely impressive Anglican Cathedral with entertainment from a Beatles tribute band. That will certainly be a hard act to follow at the next conference in 2017. Brian Tompkins took the reigns as the new BCLA president. Professor Fiona Stapleton was the recipient of the BCLA Gold Medal Award. The winner of the poster competition was Dorota Szczesna-Iskander with a poster entitled ‘Dry Contact lens poor wettability and visual performance’. Second place was Renee Reeder with her poster entitled ‘Abnormal Rosacea as a differential diagnosis in corneal scarring’. And third place was Maria Jesus Gonzalez-Garcia with her poster entitled ‘Dry Effect of the Environmental Conditions on Tear Inflammatory Mediators Concentration in Contact Lens Wearers’. The photographic competition winner was Professor Wolfgang Sickenberger from Jena in Germany. The Editorial Panel of CLAE met at the BCLA conference for their first biannual meeting. The journal metrics were discussed. In terms of number of submissions of new papers CLAE seems to have plateaued after seeing a rapid growth in the number of submissions over the last few years. The increase over the last few years could be attributed to the fact that CLAE was awarded an impact factor for the first time in 2012. This year it seems that impact factors across nearly all ophthalmic related journals has dropped. This could in part be due to the fact that last year was a ‘Research Exercise Framework (REF) year for UK universities, where they are judged on quality of their research output. The next REF is in 2020 so we may see changes nearing that time. Looking at article downloads, there seems to be a continued rise in figures. Currently CLAE attracts around 85,000 downloads per year (this is an increase of around 10,000 per year for the last few years) and the 2015 prediction is 120,000! With this in mind and with other contributing factors too, the BCLA has decided to move to online delivery of CLAE to its members starting from issue 5 of 2015. Some members do like to flick through the pages of a hard copy of the journal so members will still have the option of receiving a hard copy through the post but the default journal delivery method will now be online. The BCLA office will send various alerts and content details to members email addresses. To access CLAE online you will need to log in via the BCLA web page, currently you then click on ‘Resources’ and then under ‘Free and Discounted Publications’ you will see CLAE. This actually takes you to CLAE’s own webpage (www.contactlensjournal.com) but you need to log in via the BCLA web page. The BCLA plans to change these weblinks so that from the BCLA web page you can link to the journal website much more easily and you have the choice of going directly into the general website for CLAE or straight to the current issue. In 2016 you will see an even easier way of accessing CLAE online as the BCLA will launch a CLAE application for mobile devices where the journal can be downloaded as a ‘flick-book’. This is a great way of bringing CLAE into the modern era where people access their information in newer ways. For many the BCLA conference was part of a very busy conference week as it was preceded by the International Association of Contact Lens Educators’ (IACLE) Third World Congress, held in Manchester on the 4 days before the BCLA conference. The first and second IACE World Congresses were held in Waterloo, Canada in 1994 and 2000 respectively and hosted by Professor Des Fonn. Professor Fonn was the recipient of the first ever IACLE lifetime achievement award. The Third IACLE World Congress saw more than 100 contact lens educators and industry representatives from around 30 countries gather in the UK for the four-day event, hosted by The University of Manchester. Delegates gained hands-on experience of innovations in teaching, such as learning delivery systems, the use of iPads in the classroom and for creating ePub content, and augmented and virtual reality technologies. IACLE members around the world also took part via a live online broadcast. The Third IACLE World Congress was made possible by the generous support of Sponsors Alcon, CooperVision and Johnson & Johnson Vision Care., for more information look at the IACLE web page (www.iacle.org).

Structural design of contact lens-based drug delivery systems; in vitro and in vivo studies of ocular triggering mechanisms

This study identifies and investigates the potential use of in-eye trigger mechanisms to supplement the widely available information on release of ophthalmic drugs from contact lenses under passive release conditions. Ophthalmic dyes and surrogates have been successfully employed to investigate how these factors can be drawn together to make a successful system. The storage of a drug-containing lens in a pH lower than that of the ocular environment can be used to establish an equilibrium that favours retention of the drug in the lens prior to ocular insertion. Although release under passive conditions does not result in complete dye elution, the use of mechanical agitation techniques which mimic the eyelid blink action in conjunction with ocular tear chemistry promotes further release. In this way differentiation between passive and triggered in vitro release characteristics can be established. Investigation of the role of individual tear proteins revealed significant differences in their ability to alter the equilibrium between matrix-held and eluate-held dye or drug. These individual experiments were then investigated in vivo using ophthalmic dyes. Complete elution was found to be achievable in-eye; this demonstrated the importance of that fraction of the drug retained under passive conditions and the triggering effect of in-eye conditions on the release process. Understanding both the structure-property relationship between drug and material and in-eye trigger mechanisms, using ophthalmic dyes as a surrogate, provides the basis of knowledge necessary to design ocular drug delivery vehicles for in-eye release in a controllable manner.

Visual and quality outcomes following bilateral implantation of a trifocal intraocular lens

Purpose: To examine visual outcomes following bilateral implantation of the FineVision trifocal intraocular lens (IOL; PhysIOL, Liège, Belgium). Methods: 26 patients undergoing routine cataract surgery were implanted bilaterally with the FineVision Trifocal IOL and followed up post-operatively for 3 months. The FineVision optic features a combination of 2 diffractive structures, resulting in distance, intermediate (+1.75 D add) and near vision (+3.50 D add) zones. Apodization of the optic surface increases far vision dominance with pupil aperture. Data collected at the 3 month visit included uncorrected and corrected distance (CDVA) and near vision; subjective refraction; defocus curve testing (photopic and mesopic); contrast sensitivity (CSV-1000); halometry glare testing and a questionnaire (NAVQ) to gauge near vision function and patient satisfaction. Results: The cohort comprised 15 males and 11 females, aged 52.5–82.4 years (mean 70.6 ± 8.2 years). Mean post-operative UDVA was 0.22 ± 0.14 logMAR, with a mean spherical equivalent refraction of +0.02 ± 0.35 D. Mean CDVA was 0.13 ± 0.10 logMAR monocularly, and 0.09 ± 0.07 logMAR binocularly. Defocus curve testing showed an extensive range of clear vision in both photopic and mesopic conditions. Patients showed high levels of satisfaction with their near vision (mean ± 0.9 ± 0.6, where 0 = completely satisfied, and 4 = completely unsatisfied) and demonstrated good spectacle independence. Conclusion: The FineVision IOL can be considered in patients seeking spectacle dependence following cataract surgery, and provide good patient satisfaction with uncorrected vision.

Fitting an MSD (Mini Scleral Design) rigid contact lens in advanced keratoconus with INTACS

Keratoconus is a bilateral degenerative disease characterized by a non-inflammatory, progressive central corneal ectasia (typically asymmetric) and decreased vision. In its early stages it may be managed with spectacles and soft contact lenses but more commonly it is managed with rigid contact lenses. In advanced stages, when contact lenses can no longer be fit, have become intolerable, or corneal damage is severe, a penetrating keratoplasty is commonly performed. Alternative surgical techniques, such as the use of intra-stromal corneal ring segments (INTACS) have been developed to try and improve the fit of rigid contact lenses in keratoconic patients and avoid penetrating keratoplasties. This case report follows through the fitting of rigid contact lenses in an advanced keratoconic cornea after an INTACS procedure and discusses clinical findings, treatment options, and the use of mini-scleral and scleral lens designs as they relate to the challenges encountered in managing such a patient. Mini-scleral and scleral lenses are relatively easy to fit, and can be of benefit to many patients, including advanced keratoconic patients, post-INTAC patients and post-penetrating keratoplasty patients. © 2011 British Contact Lens Association.

The development of biomaterials for contact lens applications:effects of wear modality on materials design

The successful design of polymers for contact lens applications depends on the ability to provide a balance of properties appropriate to the ocular environment. Principal relevant aspects of the anterior eye are the tear film, eyelid and cornea, which govern the requirements for surface properties, modulus and oxygen permeability, respectively. Permeability requirements and the developing view of the needs of the cornea, in terms of oxygen consumption and the particular roles of fluorine and silicon in the design of silicone hydrogels, which have proved to be the most successful family of materials for this demanding application, are discussed. The contact lens field is complicated by the fact that contact lenses are used in a range of wear modalities, the extremes of which can conveniently be classified as lenses that are disposed of at the end of a single period of daily wear and those used for 30. days of successive day-and-night periods, frequently referred to as extended or continuous wear. As silicone hydrogels developed, in the decade following their launch there has been a progressive trend in properties taking both modulus and water content closer to those of conventional hydrogels. This is particularly evident in the family of daily disposable contact lenses that have appeared since 2008.

Development of an instrument to measure high school students' global awareness and attitudes: Looking through the lens of social sciences

The purpose of this study was to develop an instrument to measure high school students’ perspectives on global awareness and attitudes toward social issues. The research questions that guided this study were: (a) Can acceptable validity and reliability estimates be established for an instrument developed to measure high schools students' global awareness? (b) Can acceptable validity and reliability estimates be established for an instrument developed to measure high schools students' attitudes towards global social issues? (c) What is the relationship between high school students’ GPA, race/ethnicity, gender, socio-economic status, parents’ education, getting the news, reading and listening habits, the number of classes taken in the social sciences, whether they speak a second language, and have experienced living in or visiting other countries, and their perception of global awareness and attitudes toward global social issues. ^ An ex post facto research design was used and the data were collected using a 4-part Likert-type survey. It was administered to 14 schools in the Miami-Dade County, Florida area to 704 students. A factor analysis with an orthogonal varimax rotation was vii used to select the factors that best represented the three constructs – global education, global citizenship, and global workforce. This was done to establish construct validity. Cronbach’s alpha was used to determine the reliability of the instrument. Descriptive statistics and a hierarchical multiple regression were used for the demographics to establish their relationship, if any, to the findings. ^ Key findings of the study were that reliable and valid estimates can be developed for the instrument. The multiple regression analysis for model 1 and 2 accounted for a variance of 3% and 5% for self-perceptions of global awareness (factor 1). The regression model also accounted for a 5% and 13% variance in the two models for attitudes toward global social issues (factor 2). The demographics that were statistically significant were: ethnicity, gender, SES, parents’ education, listening to music, getting the news, speaking a second language, GPA, classes taken in the social sciences, and visiting other countries. An important finding for the study was those attending public schools (as opposed to private schools) had more positive attitudes towards global social issues (factor 2) The statistics indicated that these students had taken history, economics, and social studies – a curriculum infused with global perspectives.^

Distribution of Ivory Coast microtektite layer

During the present study the Ivory Coast microtektite layer was found in cores from five equatorial Atlantic sites, bringing the total number of Ivory Coast microtektite-bearing cores to eleven. The strewn field appears to be restricted to between 9°N and 12°S latitude. There is a general increase in the concentration of microtektites towards the Bosumtwi crater, which is generally thought to be the source of the Ivory Coast tektites. The relationship between the onset of the Jaramillo subchron and the Ivory Coast microtektite layer has been investigated in six cores. A plot of the difference in depth between the base of the Jaramillo subchron and the microtektite layer versus sediment accumulation rate was used to determine the average post-depositional remanent magnetization (PDRM) acquisition depth and the age difference between the onset of the Jaramillo subchron and the deposition of the microtektites. Assuming that the PDRM acquisition depth does not vary with sediment accumulation rate, we find that the average PDRM acquisition depth is 7 cm and that the microtektites were deposited approximately 8 ky after the onset of the Jaramillo subchron. This indicates that the impact responsible for the Ivory Coast tektites and microtektites could not be causally related to the geomagnetic reversal at the base of the Jaramillo subchron.

Can aberrometry provide rapid and reliable measures of subjective depth of focus following multifocal intraocular lens implantation?

Purpose: To determine whether the ‘through-focus’ aberrations of a multifocal and accommodative intraocular lens (IOL) implanted patient can be used to provide rapid and reliable measures of their subjective range of clear vision. Methods: Eyes that had been implanted with a concentric (n = 8), segmented (n = 10) or accommodating (n = 6) intraocular lenses (mean age 62.9 ± 8.9 years; range 46-79 years) for over a year underwent simultaneous monocular subjective (electronic logMAR test chart at 4m with letters randomised between presentations) and objective (Aston open-field aberrometer) defocus curve testing for levels of defocus between +1.50 to -5.00DS in -0.50DS steps, in a randomised order. Pupil size and ocular aberration (a combination of the patient’s and the defocus inducing lens aberrations) at each level of blur was measured by the aberrometer. Visual acuity was measured subjectively at each level of defocus to determine the traditional defocus curve. Objective acuity was predicted using image quality metrics. Results: The range of clear focus differed between the three IOL types (F=15.506, P=0.001) as well as between subjective and objective defocus curves (F=6.685, p=0.049). There was no statistically significant difference between subjective and objective defocus curves in the segmented or concentric ring MIOL group (P>0.05). However a difference was found between the two measures and the accommodating IOL group (P<0.001). Mean Delta logMAR (predicted minus measured logMAR) across all target vergences was -0.06 ± 0.19 logMAR. Predicted logMAR defocus curves for the multifocal IOLs did not show a near vision addition peak, unlike the subjective measurement of visual acuity. However, there was a strong positive correlation between measured and predicted logMAR for all three IOLs (Pearson’s correlation: P<0.001). Conclusions: Current subjective procedures are lengthy and do not enable important additional measures such as defocus curves under differently luminance or contrast levels to be assessed, which may limit our understanding of MIOL performance in real-world conditions. In general objective aberrometry measures correlated well with the subjective assessment indicating the relative robustness of this technique in evaluating post-operative success with segmented and concentric ring MIOL.

Monsters Take to the Streets! Monstrous Street-Art as Pedagogy of Resistance to Post-Olympic Regeneration in Hackney Wick?

This chapter explores geographies of gentrification and resistance in relation to the monstrous through the lens of street-art in post-Olympic London. It takes as a geographic case study Hackney Wick, which has for a long time been a bastion of alternative and creative living due to cheap rents in large, ex-industrial warehouse spaces. The artistic sociality of the area is imbued within its landscape, as prolific street artists have adorned ex-industrial warehouses and canal-side walls with graffiti and murals. Since the announcement of the 2012 Olympic Games, the area has been a site of intense political and aesthetic contestation. The post-Olympic legacy means that the area has been earmarked for redevelopment, with current residents facing the possibility of joining thousands already displaced by the games. The anxiety of dispossession is reflected by monstrous characters and sinister disembodied teeth, eyes and fingers embedded within the landscape, painted by local artists. Using geographically sensitive mobile and visual methodology to document the landscape and artwork, the chapter analyses and interprets the monstrous themes using a range of theorists including Mikhail Bakhtin, Georges Bataille and Nick Land. I argue that monstrous street-art lays visible claim to public territory for aesthetic purposes at odds with the visions of redevelopers and the needs of capital. Whilst street-art and graffiti do not fit easily within frameworks of organized political resistance or collective social movements, they operate as a kind of epistemological transgression that triggers transformative affects in the viewer. This creates conditions for pedagogies of resistance to gentrification by expressing and mobilizing political affects such as anger and anxiety, raising awareness of geographical politics, and encouraging the viewer to question the status quo of the built environment.

Constructivism, constitutionalism and the EU's area of freedom security and justice post-Lisbon

This essay addresses the fundamental conceptual challenges which face the development of the Area of Freedom Security and Justice (AFSJ) in the post-Lisbon Treaty era. It argues that Onuf style constructivism is a valid lens with which to examine the development of the AFSJ to date, involving as it does the development of a shared understanding by practitioners, predominantly law enforcement and prosecution professionals, within the structures provided for them, in order to develop a completely new area of law and practice. While this approach will continue to need to be deployed in the development of further new operational areas, such as cybercrime, a new approach is now required, that of constitutionalism. A variety of forms of constitutionalism are then examined in order to establish their suitability as a mode of analysis for these developments.